Grammarly Writing Score Integration

Overview

Integrate Grammarly's Writing Score API into your application. Score documents, track writing quality over time, and provide feedback. The API evaluates text across four dimensions: engagement, correctness, clarity, and tone.

Prerequisites

Completed grammarly-install-auth setup
Understanding of score dimensions

Instructions

Step 1: Typed Score Client

// src/grammarly/scoring.ts
interface WritingScore {
  overallScore: number;
  engagement: number;
  correctness: number;
  clarity: number;
  tone: number;
}

interface ScoreRequest {
  text: string;
  audienceType?: 'general' | 'knowledgeable' | 'expert';
  domain?: 'academic' | 'business' | 'general' | 'email' | 'casual';
}

async function scoreDocument(req: ScoreRequest, token: string): Promise<WritingScore> {
  const response = await fetch('https://api.grammarly.com/ecosystem/api/v2/scores', {
    method: 'POST',
    headers: { 'Authorization': `Bearer ${token}`, 'Content-Type': 'application/json' },
    body: JSON.stringify(req),
  });
  if (!response.ok) throw new Error(`Grammarly API ${response.status}: ${await response.text()}`);
  return response.json();
}

Step 2: Batch Document Scoring

async function batchScore(documents: string[], token: string): Promise<WritingScore[]> {
  const results: WritingScore[] = [];
  for (const doc of documents) {
    if (doc.split(/\s+/).length < 30) {
      console.warn('Skipping: minimum 30 words required');
      continue;
    }
    const score = await scoreDocument({ text: doc }, token);
    results.push(score);
    await new Promise(r => setTimeout(r, 500)); // Rate limit buffer
  }
  return results;
}

Step 3: Quality Threshold Enforcement

interface QualityGate {
  minOverall: number;
  minCorrectness: number;
  minClarity: number;
}

function checkQualityGate(score: WritingScore, gate: QualityGate): { passed: boolean; issues: string[] } {
  const issues: string[] = [];
  if (score.overallScore < gate.minOverall) issues.push(`Overall ${score.overallScore} < ${gate.minOverall}`);
  if (score.correctness < gate.minCorrectness) issues.push(`Correctness ${score.correctness} < ${gate.minCorrectness}`);
  if (score.clarity < gate.minClarity) issues.push(`Clarity ${score.clarity} < ${gate.minClarity}`);
  return { passed: issues.length === 0, issues };
}

// Usage: enforce quality before publishing
const score = await scoreDocument({ text: blogPost }, token);
const gate = checkQualityGate(score, { minOverall: 80, minCorrectness: 90, minClarity: 75 });
if (!gate.passed) console.error('Quality gate failed:', gate.issues);

API Limits

Limit	Value
Max text size	4 MB
Max characters	100,000
Min words	30

Error Handling

Error	Cause	Solution
`400`	Text too short	Ensure >= 30 words
`413`	Text too large	Split into chunks < 100K chars
`429`	Rate limited	Implement exponential backoff

Resources

Next Steps

For AI and plagiarism detection, see grammarly-core-workflow-b.